Gibbs Christopher M, Nelson Brody, Combs Taylor, Moody Devon, Kaufmann Robert A
Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA.
Element Materials Technology, Fairfield, OH.
J Hand Surg Glob Online. 2023 Feb 8;5(3):265-271. doi: 10.1016/j.jhsg.2022.12.008. eCollection 2023 May.
The goal of this study was to test the static and dynamic strength and loosening resistance of the posterior flange of a novel total elbow arthroplasty. We also examined the forces experienced by the ulnohumeral joint and the posterior olecranon during expected elbow use.
Static stress analysis was performed for 3 flange sizes. Failure testing was conducted on 5 flanges (1 medium size and 4 small sizes). Loading occurred to reach 10,000 cycles. If this was accomplished, the cyclic load was increased until failure occurred. If failure occurred before 10,000 cycles, a lower force was employed. The safety factor for each implant size was calculated, and implant failure or loosening was observed.
Static testing revealed a safety factor of 6.6, 5.74, and 4.53 for the small, medium, and large flanges, respectively. The medium-sized flange completed 10,000 cycles with 1,000 N at 1 Hz, and then the force was increased until it failed at 23,000 cycles. Two small-sized flanges failed at 2,345 and 2,453 cycles, respectively, when loaded with 1,000 N. Two more small flanges were loaded with 729 N for 10,000 cycles, and then the cyclic load was continued until they failed at 17,000 and 17,340 cycles, respectively. No screw loosening was noted in any specimens.
This study demonstrates that the posterior flange withstood static and dynamic forces greater than what is expected during in vivo use of a novel total elbow arthroplasty design. Static strength calculation and cyclic loading demonstrate that the medium-sized posterior flange is stronger than the small-sized posterior flange.
Ensuring that the ulnar body component and the posterior flange maintain secure connectivity with the polyethylene wear component may be beneficial to the proper function of a novel nonmechanically linked total elbow arthroplasty.
本研究的目的是测试一种新型全肘关节置换术后侧凸缘的静态和动态强度以及抗松动性。我们还研究了在预期的肘部使用过程中尺肱关节和尺骨鹰嘴后侧所承受的力。
对3种凸缘尺寸进行静态应力分析。对5个凸缘（1个中等尺寸和4个小尺寸）进行失效测试。加载至10000次循环。如果完成此操作，则增加循环载荷直至发生失效。如果在10000次循环之前发生失效，则采用较低的力。计算每种植入物尺寸的安全系数，并观察植入物失效或松动情况。
静态测试显示，小、中、大尺寸凸缘的安全系数分别为6.6、5.74和4.53。中等尺寸的凸缘在1Hz下以1000N完成了100００次循环，然后增加力直至在23000次循环时失效。两个小尺寸凸缘在加载1000N时分别在2345次和2453次循环时失效。另外两个小凸缘在729N下加载10000次循环，然后继续循环加载直至分别在17000次和17340次循环时失效。在任何标本中均未观察到螺钉松动。
本研究表明，新型全肘关节置换术设计在体内使用期间，后侧凸缘承受的静态和动态力大于预期。静态强度计算和循环加载表明，中等尺寸的后侧凸缘比小尺寸的后侧凸缘更强。
确保尺骨体组件和后侧凸缘与聚乙烯磨损组件保持牢固连接，可能有利于新型非机械连接全肘关节置换术的正常功能。
